JP2012095010A - Image reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To read out each pixel data stored in a memory from a CIS (Contact Image Sensor) in a pixel arrangement order and execute various processes on an image with accuracy while suppressing the manufacturing cost even when any one of CISs with different output types is provided, in an image reading device.SOLUTION: An image reading device 1 has: a memory 3 storing each pixel data outputted from a CIS 2 in an address depending on an output type of the CIS 2; and a storage control circuit 4. The storage control circuit 4 changes over a method for reading the pixel data from the memory 3, based on output type information for the CIS 2. Thereby, each pixel data can be read out from the memory 3 in a pixel arrangement order to accurately execute various processes on an image even when any one of CISs 2 with different output types is provided. Further, since the storage control circuit corresponding to the CIS 2 is not required to be prepared for each output type of the CIS 2 at manufacturing for the purpose of performing image processing with accuracy, components can be commonalized.

Description

  The present invention relates to an image reading apparatus that reads an image of a document.

  Conventionally, an image of a document is read by a CIS (Contact Image Sensor), the read image data is stored in a memory, and the image data is read from the memory and subjected to various kinds of processing during image correction processing or the like. An image reading apparatus is known.

  The CIS has a plurality of light receiving elements arranged in one direction. An image of a document that moves relative to each light receiving element is read line by line by the light receiving elements, and the amount of light received by each light receiving element is calculated. Each pixel data is used. The image reading apparatus writes each pixel data output from the CIS into the memory.

  Such CIS includes a linear output type and a separate output type that differ in the output method of pixel data. The linear output type outputs each pixel data in the order of pixel arrangement. The separated output type separates each pixel into an odd-numbered pixel group composed of odd-numbered pixels counted from the reference pixel and an even-numbered pixel group composed of even-numbered pixels counted from the reference pixel. The pixel data is output in the pixel arrangement order for each of the separated groups.

  In the image reading apparatus, the writing position of the pixel data in the memory differs depending on which output type CIS is used. Therefore, in the conventional image reading apparatus, for each CIS output type, an image reading circuit that reads out pixel data corresponding to the CIS in the order of pixel arrangement is prepared and incorporated at the time of manufacture. It reads out in the pixel arrangement order so that various processes on the image can be executed accurately. However, at the time of manufacturing, it is necessary to prepare an image reading circuit corresponding to the CIS for each output type of the CIS, which increases the manufacturing cost.

  By the way, an image reading apparatus that controls a write address of read image data by CIS in a memory in accordance with a CIS output method is known (for example, see Patent Document 1). Moreover, although it is not an image reading device, it can realize a CIS that can divide the read image into a plurality of blocks and output the image of each block in parallel (for example, see Patent Document 2) and a reading speed according to the resolution. And high-speed CIS (see, for example, Patent Document 3) is known. However, it is difficult to solve the above problems with the techniques described in Patent Documents 1 to 3.

JP 2006-191362 A JP-A-6-189080 JP 11-234473 A

  The present invention has been made to solve the above-described conventional problems, and each pixel stored in the storage means from the CIS while suppressing the manufacturing cost regardless of which of the CISs having different output types is provided. An object of the present invention is to provide an image reading apparatus capable of reading data in the order of pixel arrangement and accurately executing various processes on an image.

  In order to achieve the above object, an image reading apparatus of the present invention has a plurality of light receiving elements arranged in one direction, and an image of an original that moves relative to the plurality of light receiving elements is displayed on the line by the light receiving elements. CIS (Contact Image Sensor) that reads each pixel and uses the amount of light received by each light receiving element as each pixel data of the image, storage means for storing image data of each line read by the CIS, and reading by the CIS Storage control means for storing the image data of each line output from the CIS in the storage means, image reading means for reading out the image data of each line stored in the storage means, and reading by the image reading means. Processing means capable of executing various processes based on the output image data of each line, and the storage control means outputs each pixel data from the CIS In the image reading apparatus that stores the pixel data in the storage means so that the order of the addresses of the pixel data is the same, the CIS is a first output type that outputs the pixel data in the order of pixel arrangement. Or each pixel is separated into an odd pixel group consisting of odd-numbered pixels counted from a reference pixel and an even pixel group consisting of even-numbered pixels counted from the reference pixel Then, it is a second output type that outputs pixel data in order of pixel arrangement for each of the separated groups, and the user determines whether the CIS is the first output type or the second output type. A type discriminating means for inputting, when the storage discriminating means judges that the CIS is the first output type by the type discriminating means. Each pixel data is stored in order from the preset first start address of the storage means, and when the CIS is determined to be the second output type by the type determination means, it is output from the CIS. It is determined whether each pixel data is the odd pixel group or the even pixel group, and the pixel data determined as the odd pixel group is stored in order from a preset second start address of the storage means. The pixel data determined as the even-numbered pixel group is stored in order from a preset third start address of the storage means, and the image reading means is configured to output the first output of the CIS by the type determination means. When it is determined that it is a type, each pixel is read out in order from the first start address, thereby Data is read in order of pixel arrangement, and when the CIS is determined to be the second output type by the type determining means, the odd pixel group is sequentially read from the second start address and the third start address. Each pixel data is read in order of pixel arrangement by alternately reading pixel data and pixel data of the even-numbered pixel group.

  In the present invention, the CIS is one of a plurality of predetermined resolutions of the amount of light received by the light receiving element, and resolution input means for inputting which of the plurality of resolutions is the resolution. Pixel storage means for temporarily storing the pixel data transmitted from the image reading means to the processing means, and a pointer for incrementing a pointer of the pixel storage means each time the pixel data is stored in the pixel storage means Preferably, the pointer increment means adjusts the number of increments of the pointer based on the resolution information input by the resolution input means.

  According to the present invention, regardless of the output type in which each read pixel data is output in a different manner, the image reading means is based on the CIS output type information determined by the type determining means. In addition, each pixel data output from the CIS and stored in the storage means can be read in the order of pixel arrangement, and various processes on the image can be executed accurately. In addition, in order to perform image processing accurately, it is not necessary to prepare an image reading means corresponding to CIS for each output type of CIS at the time of manufacturing, and therefore, it is possible to share parts. Manufacturing costs can be reduced.

1 is an electrical block diagram of an image reading apparatus according to an embodiment of the present invention. 5 is a flowchart showing a part of a procedure of a process of reading pixel data stored in a memory in the apparatus. The flowchart which shows said remaining procedure.

  Hereinafter, an image reading apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of the image reading apparatus of the present embodiment. The image reading apparatus 1 is applied to a scanner or the like that reads an image of a document. The image reading apparatus 1 includes a CIS (Contact Image Sensor) 2 for reading the image, a memory 3 (storage means) for storing image data read by the CIS 2, and image data read by the CIS 2 in the memory 3. A storage control circuit 4 (storage control means, image reading means) for storing and reading out image data from the memory 3 as appropriate is provided. The storage control circuit 4 changes the contents of the data read process according to the output type and resolution type described later of the CIS 2.

  In addition, the image reading apparatus 1 performs a predetermined process on the image data read by the storage control circuit 4 to perform a gamma correction circuit 5 (processing unit) that performs image gamma correction, and a gamma correction circuit 5 that performs gamma correction from the storage control circuit 4. A FIFO (First in, First Out) circuit 6 (pixel storage means) is provided in the data transmission path to the correction circuit 5 and temporarily stores image data. Further, the image reading apparatus 1 includes an input circuit 7 (resolution input means) for inputting the type of resolution of the CIS 2 and a microprocessor 8 (type discrimination means) for controlling each circuit and determining the output type of the CIS 2. ).

  The CIS 2 is a line sensor having a plurality of light receiving elements arranged in one direction. This line sensor reads an image of a document that moves relative to a plurality of light receiving elements, line by line by a light receiving element at regular intervals or at constant movement distances, and determines the amount of light received by each light receiving element. The pixel data is output in the pixel arrangement order for each line. The arrangement direction of the light receiving elements is the same as the sub-scanning direction of the document. In order to relatively move the light receiving element and the original, the CIS 2 may be configured to be movable in the main scanning direction of the original, or the original is placed in the image reading apparatus 1 at right angles to the arrangement direction of the light receiving elements. A moving mechanism for moving in the direction may be provided.

  The CIS 2 may be either a linear output type or a separated output type that has different pixel data output methods. The linear output type (first output type) outputs each pixel data in the order of pixel arrangement. In the separated output type (second output type), each pixel is an odd-numbered pixel group consisting of pixels arranged oddly from the reference pixel (hereinafter referred to as odd-numbered pixels), and even-numbered from the reference pixel. The pixel data is separated into even pixel groups composed of arranged pixels (hereinafter referred to as even pixels), and pixel data is output in the pixel arrangement order for each of the separated groups. The image reading apparatus 1 is configured to be communicable with the CIS 2 regardless of the output type of the CIS 2. In the case of the separation output type, the CIS 2 first transmits pixel data of the odd pixel group, and then transmits pixel data of the even pixel group. Further, the CIS 2 is one of a plurality of types in which the resolution of the amount of light received by each light receiving element is determined in advance, and the image reading apparatus 1 is configured to be able to handle any of these types of resolutions. The resolution of the CIS2 in this embodiment is, for example, one of two types of 8 bits and 16 bits (actually used is 12-bit pixel data).

  The memory 3 is configured by an SDRAM (Synchronous Dynamic Random Access Memory) that can store image data of each line read by the CIS 2. The storage unit of the memory 3 is, for example, 8 bits.

  The storage control circuit 4 is configured by a DMA I / F (Direct Memory Access Interface) or the like. The storage control circuit 4 stores the image data of each line output from the CIS 2 in the memory 3. Each line of image data consists of a line of pixel data. The storage control circuit 4 stores the pixel data in the memory 3 so that the output order of the pixel data from the CIS 2 and the address order of the pixel data are the same for each line.

  The storage control circuit 4 (pointer increment means) has a function of incrementing the pointer of the FIFO circuit 6 every time pixel data is stored in the FIFO circuit 6.

  The FIFO circuit 6 includes a buffering type flow control circuit that temporarily stores pixel data transferred from the storage control circuit 4 to the gamma correction circuit 5. This flow control circuit stores the transferred pixel data until the gamma correction circuit 5 is ready for processing, and then outputs it to the gamma correction circuit 5. This output order is the same as the order in which the pixel data is input to the FIFO circuit 6. The storage unit of the FIFO circuit 6 is 8 bits, for example.

  The input circuit 7 is configured by an interface or the like for inputting which of the plurality of types of resolution of each light receiving element of the CIS 2 is used. In this embodiment, the resolution is two types of 8 bits and 16 bits. It is possible to input any of them. The input circuit 7 includes a two-pole switch such as a toggle switch, a waveform switch, or a slide switch for such input. Based on the input information about the resolution, the storage control circuit 4 adjusts the number of increments of the pointer of the FIFO circuit 6. Specifically, the storage control circuit 4 sets the number of increments to 1 when the resolution is input as 8 bits, and sets the number of increments as 2 when the resolution is input as 16 bits. The input circuit 7 may be capable of inputting not only the resolution type but also other information.

  The microprocessor 8 receives the pixel data output from the CIS 2, and the microprocessor 8 transfers the input pixel data to the storage control circuit 4. The storage control circuit 4 stores the transferred pixel data in the memory 3. Further, the microprocessor 8 determines whether the CIS 2 is a linear output type or a separated output type. This determination processing is performed according to the number of terminals to which pixel data is actually input among the terminals provided for inputting pixel data from the CIS 2 in the microprocessor 8, for example. If the number of terminals is one, CIS2 is determined as a linear output type, and if the number of terminals is two, it is determined as a separate output type.

  Next, data write processing to the memory 3 in the storage control circuit 4 will be described. When the microprocessor 8 determines that the CIS 2 is a linear output type, the storage control circuit 4 stores each pixel data in order from the preset first start address of the memory 3. When there are a plurality of line images read by CIS2, the pixel data string of the line image read first is stored as described above. Then, the pixel data string of the line image read after the next is stored in the same address order as the line reading order, following the address area in which the first line image is stored.

  When the microprocessor 8 determines that the CIS 2 is the separation output type, the storage control circuit 4 determines whether each pixel data output from the CIS 2 is an odd pixel group or an even pixel group. In this determination processing, for example, the number of odd pixels is calculated based on the preset number of CIS2 pixels or the number of CIS2 pixels input from the input circuit 7. Then, the number of pixel data output from the CIS 2 is counted, and it is determined that the output pixel data is odd-numbered pixel data until the counted number becomes equal to the calculated number of odd-numbered pixels, The pixel data output thereafter is determined as even-numbered pixel data.

  Then, the storage control circuit 4 sequentially stores the pixel data determined as the odd pixel group from the preset second start address of the memory 3 and stores the pixel data determined as the even pixel group in the memory 3 in advance. It memorizes in order from the set third start address. When there are a plurality of line images read by the CIS2, the odd pixel group and the even pixel group of the line image read first are stored as described above. Then, the odd-numbered pixel group and the even-numbered pixel group of the line image read from the next onward are respectively continuous to the continuation of the address area in which the odd-numbered pixel group and the even-numbered pixel group of the first line image are respectively stored, Stored in the same address order as the line reading order. The first start address, the second start address, and the third start address can be set by the input circuit 7, and the first start address and the second start address may be the same. The third start address is set to have a larger address value than the second start address.

  Next, pixel data reading processing from the memory 3 in the storage control circuit 4 will be described. When the microprocessor 8 determines that the CIS 2 is a linear output type, the storage control circuit 4 reads pixel data in order from the first start address, whereby each pixel data is arranged in line order and pixel arrangement for each line. Read sequentially. When the microprocessor 8 determines that the CIS 2 is a separate output type, the storage control circuit 4 sequentially outputs the pixel data of the odd pixel group and the pixel data of the even pixel group in order from the second start address and the third start address. Are alternately read out, whereby each pixel data is read out in the order of lines and in the order of pixel arrangement for each line. Then, the storage control circuit 4 sequentially writes the read pixel data to the FIFO circuit 6.

  2 and 3 show an example of a detailed procedure of the pixel data reading process. As shown in FIG. 2, when the microprocessor 8 determines that the CIS 2 is a linear output type (Yes in S101), the storage control circuit 4 sets the pointer of the memory 3 to the first start address (S102). ).

  When the input circuit 7 inputs that the resolution of each light receiving element of the CIS 2 is 8 bits (Yes in S103), the storage control circuit 4 reads the pixel data at the address specified by the pointer of the memory 3 ( In S104, the read pixel data is written in the storage area designated by the pointer in the FIFO circuit 6 (S105).

  Then, the storage control circuit 4 increments the pointer of the memory 3 once (S106), and increments the pointer of the FIFO circuit 6 once (S107). If reading of all the pixel data has not been completed (No in S108), the processing of S104 to S107 is repeated, and the pixel data is read sequentially from the first start address.

  When the input circuit 7 inputs that the resolution of each light receiving element of the CIS 2 is 16 bits (No in S103, Yes in S109), the storage control circuit 4 determines the address specified by the pointer of the memory 3 and the next Is read out (S110), and the read out pixel data is written in the storage area designated by the pointer in the FIFO circuit 6 (S111).

  The storage control circuit 4 increments the pointer of the memory 3 twice (S112), and increments the pointer of the FIFO circuit 6 twice (S113). If reading of all pixel data is not completed (No in S114). , S110 to S113 are repeated.

  As shown in FIG. 3, when the microprocessor 8 determines that CIS2 is a separate output type (No in S101, Yes in S201), the storage control circuit 4 sets the pointer of the memory 3 to the second start address. Set (S202). When the input circuit 7 inputs that the resolution of each light receiving element of the CIS 2 is 8 bits (Yes in S203), the same processing as S104, S105, and S107 is executed (S204 to S206).

  If the reading of all the pixel data has not been completed (No in S207), the storage control circuit 4 sets the addresses of the third start address and the second start address to the address specified by the current pointer in the memory 3. An address with the difference added is calculated (S208), and the pointer is moved to the calculated address (S209). Thereafter, the same processing as S104 to S107 is executed (S210 to S213).

  If the reading of all pixel data has not been completed (No in S214), the storage control circuit 4 calculates an address in the memory 3 by subtracting the address difference from the address specified by the current pointer (S215). The pointer is moved to the calculated address (S216), and the process returns to S204.

  When the input circuit 7 inputs that the resolution of each light receiving element of CIS2 is 16 bits (No in S203, Yes in S217), the same processing as S110, S111, and S113 is executed (S218 to S220). ).

  If the reading of all pixel data has not been completed (No in S221), the storage control circuit 4 performs the same processing as S208, S209, S110 to S113 (S222 to S227). Thereafter, if the reading of all pixel data has not been completed (No in S228), the storage control circuit 4 performs the same processing as S215 and S216 (S229 and S230), and executes the processing after S218 again. .

  In this embodiment, the storage control circuit 4 outputs the output of the CIS 2 that is discriminated by the microprocessor 8 regardless of whether the CIS 2 outputs each read pixel data of the linear output type or the separated output type. Based on the type information, each pixel data output from the CIS 2 and stored in the memory 3 can be read in the pixel arrangement order. Therefore, the gamma correction to the image by the gamma correction circuit 5 can be executed accurately. In addition, in order to perform the gamma correction processing accurately, it is not necessary to prepare a storage control circuit corresponding to the CIS2 for each output type of the CIS2 at the time of manufacture. Therefore, it is possible to share parts. Manufacturing costs can be reduced.

  In addition, regardless of whether the resolution of the light reception amount of each light receiving element of CIS 2 is 8 bits or 16 bits, the storage control circuit 4 uses the light reception amount of each light receiving element based on the resolution information input from the input circuit 7. Can be accurately transmitted to the gamma correction circuit 5 via the FIFO circuit 6 in units of pixels. Therefore, the accuracy of gamma correction by the gamma correction circuit 5 can be improved. In addition, in order to perform the gamma correction processing accurately, it is not necessary to prepare a storage control circuit corresponding to CIS2 for each CIS2 having different resolutions at the time of manufacture, and therefore, it is possible to share parts. .

  In addition, this invention is not limited to the structure of said embodiment, A various deformation | transformation is possible according to a use purpose. For example, a processing circuit may be provided that performs data processing on the image data of each line of the document image and can execute processing other than gamma processing on the document image.

1 Image reader 2 CIS
3 Memory (memory means)
4 Storage control circuit (storage control means, image reading means, pointer increment means)
5 Gamma correction circuit (processing means)
6 FIFO circuit (pixel storage means)
7 Input circuit (resolution input means)
8 Microprocessor (Type discrimination means)

Claims (2)

An image of a document having a plurality of light receiving elements arranged in one direction and moving relative to the plurality of light receiving elements is read line by line by the light receiving elements, and the amount of light received by each light receiving element is determined for each pixel of the image. CIS (Contact Image Sensor) as data,
Storage means for storing image data of each line read by the CIS;
Storage control means for storing image data of each line read by the CIS and output from the CIS in the storage means;
Image reading means for reading image data of each line stored in the storage means;
Processing means capable of executing various processes based on the image data of each line read by the image reading means,
In the image reading apparatus, the storage control unit stores the pixel data in the storage unit so that the output order of the pixel data from the CIS and the address order of the pixel data are the same.
The CIS is a first output type that outputs the pixel data in order of pixel arrangement, or an odd pixel group composed of pixels that are odd-numbered when the pixels are counted from a reference pixel; It is a second output type that separates into even-numbered pixel groups composed of even-numbered pixels counted from the reference pixel, and outputs pixel data in the pixel arrangement order for each of the separated groups.
Type discrimination means for discriminating whether the CIS is the first output type or the second output type;
The storage control means
When the type discriminating means discriminates that the CIS is the first output type, each pixel data is stored in order from the preset first start address of the storage means,
When the CIS is determined to be the second output type by the type determination unit, it is determined whether each pixel data output from the CIS is the odd pixel group or the even pixel group, The pixel data determined to be an odd pixel group is stored in order from the preset second start address of the storage means, and the pixel data determined to be the even pixel group is stored in the preset first data of the storage means. Store in order from the start address of 3,
The image reading means includes
When the CIS is determined to be the first output type by the type determining means, the pixel data is read in order from the first start address, thereby reading each pixel data in the pixel arrangement order.
When the CIS is determined to be the second output type by the type determining means, the pixel data of the odd pixel group and the even pixel group are sequentially from the second start address and the third start address. An image reading apparatus that reads out each pixel data in the order of pixel arrangement by alternately reading out the pixel data of the first and second pixels. The CIS is any one of a plurality of predetermined resolutions of the amount of light received by the light receiving element,
Resolution input means for inputting whether the resolution is the plurality of types;
Pixel storage means for temporarily storing the pixel data transmitted from the image reading means to the processing means;
Pointer increment means for incrementing a pointer of the pixel storage means each time the pixel data is stored in the pixel storage means,
The image reading apparatus according to claim 1, wherein the pointer increment unit adjusts the number of increments of the pointer based on resolution information input by the resolution input unit.

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